lpc17xx_systick.c (6153B)
1 /********************************************************************** 2 * $Id$ lpc17xx_systick.c 2010-05-21 3 *//** 4 * @file lpc17xx_systick.c 5 * @brief Contains all functions support for SYSTICK firmware library 6 * on LPC17xx 7 * @version 2.0 8 * @date 21. May. 2010 9 * @author NXP MCU SW Application Team 10 * 11 * Copyright(C) 2010, NXP Semiconductor 12 * All rights reserved. 13 * 14 *********************************************************************** 15 * Software that is described herein is for illustrative purposes only 16 * which provides customers with programming information regarding the 17 * products. This software is supplied "AS IS" without any warranties. 18 * NXP Semiconductors assumes no responsibility or liability for the 19 * use of the software, conveys no license or title under any patent, 20 * copyright, or mask work right to the product. NXP Semiconductors 21 * reserves the right to make changes in the software without 22 * notification. NXP Semiconductors also make no representation or 23 * warranty that such application will be suitable for the specified 24 * use without further testing or modification. 25 * Permission to use, copy, modify, and distribute this software and its 26 * documentation is hereby granted, under NXP Semiconductors' 27 * relevant copyright in the software, without fee, provided that it 28 * is used in conjunction with NXP Semiconductors microcontrollers. This 29 * copyright, permission, and disclaimer notice must appear in all copies of 30 * this code. 31 **********************************************************************/ 32 33 /* Peripheral group ----------------------------------------------------------- */ 34 /** @addtogroup SYSTICK 35 * @{ 36 */ 37 38 /* Includes ------------------------------------------------------------------- */ 39 #include "lpc17xx_systick.h" 40 #include "lpc17xx_clkpwr.h" 41 42 /* If this source file built with example, the LPC17xx FW library configuration 43 * file in each example directory ("lpc17xx_libcfg.h") must be included, 44 * otherwise the default FW library configuration file must be included instead 45 */ 46 #ifdef __BUILD_WITH_EXAMPLE__ 47 #include "lpc17xx_libcfg.h" 48 #else 49 #include "lpc17xx_libcfg_default.h" 50 #endif /* __BUILD_WITH_EXAMPLE__ */ 51 52 53 #ifdef _SYSTICK 54 55 /* Public Functions ----------------------------------------------------------- */ 56 /** @addtogroup SYSTICK_Public_Functions 57 * @{ 58 */ 59 /*********************************************************************//** 60 * @brief Initial System Tick with using internal CPU clock source 61 * @param[in] time time interval(ms) 62 * @return None 63 **********************************************************************/ 64 void SYSTICK_InternalInit(uint32_t time) 65 { 66 uint32_t cclk; 67 float maxtime; 68 69 cclk = SystemCoreClock; 70 /* With internal CPU clock frequency for LPC17xx is 'SystemCoreClock' 71 * And limit 24 bit for RELOAD value 72 * So the maximum time can be set: 73 * 1/SystemCoreClock * (2^24) * 1000 (ms) 74 */ 75 //check time value is available or not 76 maxtime = (1<<24)/(SystemCoreClock / 1000) ; 77 if(time > maxtime) 78 //Error loop 79 while(1); 80 else 81 { 82 //Select CPU clock is System Tick clock source 83 SysTick->CTRL |= ST_CTRL_CLKSOURCE; 84 /* Set RELOAD value 85 * RELOAD = (SystemCoreClock/1000) * time - 1 86 * with time base is millisecond 87 */ 88 SysTick->LOAD = (cclk/1000)*time - 1; 89 } 90 } 91 92 /*********************************************************************//** 93 * @brief Initial System Tick with using external clock source 94 * @param[in] freq external clock frequency(Hz) 95 * @param[in] time time interval(ms) 96 * @return None 97 **********************************************************************/ 98 void SYSTICK_ExternalInit(uint32_t freq, uint32_t time) 99 { 100 float maxtime; 101 102 /* With external clock frequency for LPC17xx is 'freq' 103 * And limit 24 bit for RELOAD value 104 * So the maximum time can be set: 105 * 1/freq * (2^24) * 1000 (ms) 106 */ 107 //check time value is available or not 108 maxtime = (1<<24)/(freq / 1000) ; 109 if (time>maxtime) 110 //Error Loop 111 while(1); 112 else 113 { 114 //Select external clock is System Tick clock source 115 SysTick->CTRL &= ~ ST_CTRL_CLKSOURCE; 116 /* Set RELOAD value 117 * RELOAD = (freq/1000) * time - 1 118 * with time base is millisecond 119 */ 120 maxtime = (freq/1000)*time - 1; 121 SysTick->LOAD = (freq/1000)*time - 1; 122 } 123 } 124 125 /*********************************************************************//** 126 * @brief Enable/disable System Tick counter 127 * @param[in] NewState System Tick counter status, should be: 128 * - ENABLE 129 * - DISABLE 130 * @return None 131 **********************************************************************/ 132 void SYSTICK_Cmd(FunctionalState NewState) 133 { 134 CHECK_PARAM(PARAM_FUNCTIONALSTATE(NewState)); 135 136 if(NewState == ENABLE) 137 //Enable System Tick counter 138 SysTick->CTRL |= ST_CTRL_ENABLE; 139 else 140 //Disable System Tick counter 141 SysTick->CTRL &= ~ST_CTRL_ENABLE; 142 } 143 144 /*********************************************************************//** 145 * @brief Enable/disable System Tick interrupt 146 * @param[in] NewState System Tick interrupt status, should be: 147 * - ENABLE 148 * - DISABLE 149 * @return None 150 **********************************************************************/ 151 void SYSTICK_IntCmd(FunctionalState NewState) 152 { 153 CHECK_PARAM(PARAM_FUNCTIONALSTATE(NewState)); 154 155 if(NewState == ENABLE) 156 //Enable System Tick counter 157 SysTick->CTRL |= ST_CTRL_TICKINT; 158 else 159 //Disable System Tick counter 160 SysTick->CTRL &= ~ST_CTRL_TICKINT; 161 } 162 163 /*********************************************************************//** 164 * @brief Get current value of System Tick counter 165 * @param[in] None 166 * @return current value of System Tick counter 167 **********************************************************************/ 168 uint32_t SYSTICK_GetCurrentValue(void) 169 { 170 return (SysTick->VAL); 171 } 172 173 /*********************************************************************//** 174 * @brief Clear Counter flag 175 * @param[in] None 176 * @return None 177 **********************************************************************/ 178 void SYSTICK_ClearCounterFlag(void) 179 { 180 SysTick->CTRL &= ~ST_CTRL_COUNTFLAG; 181 } 182 /** 183 * @} 184 */ 185 186 #endif /* _SYSTICK */ 187 188 /** 189 * @} 190 */ 191 192 /* --------------------------------- End Of File ------------------------------ */ 193